Heating system



A. R. THOMAS HEATING SYSTEM Feb. 23, 1943.

Filed Aug. 3; 1940 |\llll ll Patented Feb. 23, 1943 HEATING SYSTEM Albert R. Thomas, Evansville, Ind,, assignor to Servel, Inc., New York, N. Y., a corporation oi Delaware ApplicationAug'ust 3,1940, Serial No. 350,241

12 Claims.

This invention relates to heating systems, and is an open type which operates at atmospheric pressure. j i

It is an object of this invention to supply steam from a boiler to a radiator or heating element having a vent to atmosphere, and to control the supply of steam so that, at heat inputs less than a predetermined maximum to the boiler, a varying quantity of air can enter the interior of the portions of the heating element. By controlling the rate of flow of steam to the heating element, more or less of the heat dissipating surface thereof can be blanketed ,off with air and kept out of direct contact with the steam, so that the eflective surface area heated by the steam can be varied to eflect regulation of the heating effected by the heating element. I v

It is another object of the invention to provide a plurality of burners to supply heat to a steam boiler of a heating system, and to sequentially control the burners, and hence the quantity of steam delivered to a heating element ofthe heatingsystem, responsive to a temperature condition affected by the heating element,

It is a further object ofthe invention to provide an improvement for controlling the heat supply to a steam boiler associated with a heating element having a vent to atmosphere, whereby the supply of steam to the heating element is reduced when steam passes into the atmosphere through the vent.-

The invention, together with the above and other objects and advantages thereof, will be better understood from the'following description taken in connection with the accompanying drawing forming a part of this specification, and of which:

Fig. 1 is a view more or less diagrammatically invention; and

Fig. 2 diagrammatically illustrates an air conditioning system and control with which the heating system in Fig. 1 is associated.

Referring to Fig. 1, the heating system includes a heating element I having a plurality of spaced headers II arranged to receive the ends of a plurality of tubes I2. The tubes I2 are inclined slightly to the horizontal and are provided with a plurality of heat dissipating flns I4. Steam is supplied to the upper part of one of the headers I I through a conduit I5 from a steam boiler I6.

The boiler I6 is provided .with a plurality of particularly concerned with a heating system of heating element to form an air blanket about a which are adapted to project the flames produced by burners I8. A combustible fuel is delivered from a source of supply through a main'conduit I9, branch conduits 20, control devices 2I to be described presently, and conduits 22 to the burners I8. Tubes 23 are connected to the branch conduits 20 and terminate in the vicinity of burners I8, whereby a pilot flame is provided for each burner when its associated control device 2 I operates so that fuel will flow to the burner.

As shown most clearly in Fig. 2, the heating tubes Il are arranged alongside each other and the burners are located at the front of the'steam boiler I6. The upper end of each heating tube Il joins a flue or riser 24 through which warm gases pass into the atmosphere from the boiler I6. A suitable hand control valve 25 is provided in con duit I5, so that manual control of steam flow to heating element I II can be effected.

When valve 25 is opened and burners I8 are operating to supply heat to the boiler I6, steam is "illustrating aheating system embodying the supplied to the upper part of one of the headers II through conduit I5. The steam entering the right-hand header II flows therefrom through the tubes I2 toward the other header, whereby a heating efiect is produced by the heating element Ill. The condensate formed in heating element I 0 returns to the boiler I 6 through a conduit 26.

.The heating element It is arranged in a duct 21 of an air conditioning system, as shown in Fig. 2. The duct 21 is connected to a suitable blower 28,

whereby air is withdrawn from an enclosure 29 through a duct 30 and passesin thermal exchange relation with heating element I 0 in duct 21. The heating eifect produced by heating element I 0 is transmitted to the air, and the heated air flowsthrough the blower 28 and a duct 3| from which the air is discharged into the enclosure 29.

As shown in Figs. 1 and 2, each of the control devices 2I includes a solenoid coil 32 formed to receive a plunger 33 to which is fixed a valve 34. When a solenoid coil 32 is electrically energized, the plunger 33 and valve 34 are raised against the force of gravity, whereby the valve 34 is moved to its open position so that fuel can flow from the conduit 20 past the valve' into conduit 22 and thence to burners I8. When a solenoid coil 32 is de-energized, the plunger 33 and valve 34 fall by gravity, whereby the valve ismoved to its closed position to shut oil flow of fuel to the burner. Each control device is provided with a coil spring 35 to insure downward movement of plunger 33 by gravity when the solenoid coil 32 is de-energized.

fire or heating tubes I'll into the lower ends of As shown in Fig. 2, the solenoid coils :2 .are

connected to conductors 36 and 31 which are connected to a suitable source of electrical supply. One terminal of each coil is connected by a conductor 38 to the conductor 36, and the other terminal of each coil is connected by a conductor 39, switch 49 and conductor 4| to the conductor 31.

In accordance with this invehtion, the switches 40 are arranged to, be controlled sequentially responsive to a temperature condition affected by the heating element l0. Any suitable mechanism may be employed to effect sequential control of switches 40, and I therefore'do not wish to be limited to the particular arrangement illustrated and now to be described. As shown, the switches 40 are of the snap-action type and include toggle arms 42 and 43 pivoted at their inner ends at 44 to a suitable support, and a coil spring 45 connected to the outer ends of the arms.

Stops 46 are provided to limit movement of lower toggle arms 43 in one direction. When moved in the opposite direction the contacts 41 at the ends of toggle arms 43 cooperate with fixed contacts 48, to complete the circuits for the solenoid coils 32.

The upper 'ends of toggle arms 42 fit into recesses 49 formed in a slide bar 50 which passes through and is movable in suitable supports The right-hand end of slide bar 50 is formed with a recess 52 to receive the upper end of a lever 53 which is pivoted intermediate its ends at 54 to a frame 55. The lower end of lever 53 is pivotally connected to a rod 56 which is secured to an expansible and contractible bellows 51 having one end thereof fixed and secured to the frame 55. A spring 58 isinterposed between the bellows 51 and the left-hand end of frame 55.

The bellows 51 is connected by a capillary tube 59 to a thermal bulb 50 located in -the enclosure 29. The bellows 51, tube 59 and bulb 60 constitute an expansible fluid thermostat containing a suitable volatile fluid which increases and decreases in volume with corresponding changes in temperature. The bellows 51 expands and contracts with increase and decrease in volume of the volatile fluid, and these movements of the bellows 51 are utilized to control the switches 40.

In Fig. 2 both of the switches 48 are closed and the solenoid coils 32 are energized, so that the valves 34 are in their open positions and 1 fuel is supplied past the valves to the burners IS. The control just described is effective to sequentially control the devices 2|, and hence control the flow of fuel to burners |8, so that the heating element II] will be capable of'maintaining the air in enclosure 29 at a desired temperature. When the airin enclosure 29, and hence the heating element |0, tends to rise above the desired temperature, the volatile fluid of the expansible fluid thermostat increases in volume and causes the bellows 51 to expand against the tension of coil spring 58. Expansion of bellows 51 imparts clockwise movement to lever 53 about pivot 54, whereby slide bar 50 is moved toward the right.

As the slide bar 50 is moved toward the right, the upper toggle arms 42 move clockwise about the pivots 44, and, when the coil springs 45 are moved past the straight line positions of the toggle arms 42and 43, the lower toggle arms move with a snap-action toward the right and the contacts." and 48lare separated and the toggle arms 43bear against the stops 46. The separation of contacts 41 and 48 opens the electrical circuits for the solenoid coils 32,

whereby the valves 34 move to their closed positions to shut off flow of fuel to burners Hi.

It will be noted in Fig. 2 that the upper toggle arms 42 of the switches 40 are at different angles with respect to the vertical. As slide bar 50 is moved toward the right, in the manner described above, the upper and lower toggle arms 42 and 43 of the left-hand switch 40 will come to a straight line position ahead of the toggle arms of the right hand switch, When this occurs and the coil spring 45 of the lefthand switch moves past the straight line position of the toggle arms, the lower toggle arm 43 will snap toward the right toseparate contacts 41 and 48 and open the circuit for the left-hand control device 2|.

It will be evident, therefore, that when the air tends to rise above the desired temperature in the enclosure 29, the movement of slide bar 50 toward the right, due to expansion of bellows 51, will first cause one of the burners |8 to become ineffective to heat boiler l6. With continued movement of slide bar 50 toward the right, the toggle arms 42 and 43 of the righthand switch will reach a straight line position,

and, when the coil spring 45 of this switch movespast the straight line position of the toggle arms, the lower toggle arm 43 will snap to the right to open the electrical circuit for the right-hand control device 2|. With the burners l8 becoming ineffective to heat boiler IS, the production of steam is reduced whereby the heating effect produced by heating element I0 is also reduced. By first opening one switch 40 and then the other switch in the manner described above, the burners are controlled sequentially responsive to a temperature condition which is affected by heating element l0.

Conversely, when the air in the enclosure 29, and hence the heating element l0, tends to fall below the desired temperature,-the volatile fluid of the expansible fluid thermostat decreases in volume and causes the bellows 51 to contract. Contraction of bellows 51 imparts counter-clockwise movement -to lever 53, whereby slide bar 59 moves toward the left. Under these conditions the'upper toggle arms 42 move counter-clockwise about the pivots 44, and, when the springs 45 have moved past the straight line positions of the toggle arms in the opposite direction from that described above, the lower toggle arms 43 move with a snap-action toward the left to close contacts 41 and 48. Closing of contacts 41 and 48 completes the electrical circuits for the solenoid coils 32, whereby the valves 34 are moved to their open positions to permit flow of fuel to the burners I8. By providing the pilot flame tubes 23, the burners l8 are immediately ignited with opening of the valves 34 so that hot gases will pass through the heating tubes IT to heat the water in boiler Hi to produce steam. The steam produced by the boiler l5 due to heating by the burners l8 causes an increase in the heating effect produced by heating element I0 which is transmitted to air flowing through the duct 21 to the enclosure 29,

Assuming that both of the switches 40 are open, and that the slide bar 50 is moving toward the left due to contraction of the bellows 51, the right-hand switch 40 will close first to cause energization of the right-hand control device 2|. With continued movement of slide bar 50 toward the left, the other switch 49 will be closed, whereby both of the control devices 2| will be energized and fuel will flow to both of the burners l8. However, the air in the enclosure 29 may tend to rise above the desired temperature such an amount as to cause only one of the switches 40 to close, so that only one of the burners will be effective to heat boiler l6.

In accordance with this invention the steam boiler system. operatessubstantially at atmospheric pressure, so that self-regulation is effected of the efiective' heat dissipating surface of the heating element M. This is accomplished by providing a steam vent 6| for heating element III which is connected to conduit 26 at the region where the latter is connected to one of the headers II. By providing the vent 6|, air can enter the interior of heating element l and blanket off part of the heat dissipating surface from direct contact by the steam at heat inputs less than maximum.

The steam boiler I6 is so proportioned andv designed that, at maximum heat input to the steam boiler l6 by both of the burners l8, and with full load'on the heating element ll) of a given capacity, all of the steam condenses in the heating element with practically no flow of steam through the vent 6| to atmosphere. The condensate formed in heating element 10 flows therefrom through conduit 26 'to the boiler l6.

' volatile fluid are utilized to control aswitch 66.

with increase and decrease in volume ofthe With all the surfaces of tubes 12 heated by steam, maximum heating efiect is obtained from heating element l0.

When the control described above has operated so that only one of the burners I8 is supplying heat to the steam boiler l6, the supply of steam to the heating element I0 is reduced. With the steam heating system operating substantially at atmospheric pressure due to the provision of the vent 6|, theheating element at heat inputs less than maximum will only be partly filled with steam and the remainder of the heating element will contain air entering through vent 6|, The quantity of air entering heating element l0 through vent 6| decreases and increases with changes in the heat input to boiler l6, so that more or less of the tubes l2 are blanketed off with air. In this way the efiective heat dissipating surface of the heating element is varied and self-regulated, and such variation in the effective heat dissipating surface is proportional to the heat input to the steam boiler I6. I

It should be understood that more than two burners I8 and control devices 2| can be employed, so that a more sensitive control of the heat input to the boiler and of the steam-supply to heating element l0 can be effected. By providing more than two burners 3 to supply heat to steam boiler l6, therefore, the rate at which steam is supplied to heating element Hi can be controlled between even narrower limits than with the two burners illustrated.

duct system stops and there is loss of air circulation at a time when steam is being supplied to the heating element In. This 'is'accomplished by providing in the vent 6| a thermal bulb 62 which is connected by a capillary tube 63 to an expansible and contractible bellows 64 fixed at one end to a suitable support 65. The thermal bulb 62, tube 63 and bellows 64 contain a suit-' able volatile fluid and form an expansible fluid thermostat like that described above associated with switches '40. The movements of bellows 64 is similar to the switches 40 and includes toggle arms 61 and 68 pivoted at their inner ends at 69 to a bracket 10, and a coil spring 'll connected to the outer ends ofthe toggle arms. The lower toggle arm 68 is not connected to the bellows 64 and is located in the path of movementthereof. Opposite to a raised knob 12 on bellows 64 is provided a reset. button 13. To the button 13 is secured a sleeve 14 which passes through an opening in bracket 10. The outer end of sleeve 14 is provided with an enlarged head 15 to receive a coil spring 16.

The upper toggle arm 61 is movable between a contact 11 and an insulated stop member 18, the contact 'Il cooperating with a contact 19 at the end of the toggle arm. One part of the conductor 36 is connected to the inner end of toggle arm 61 which is insulated in any suitable manner from the pivot '69, and the other part of conductor 36 is-connected to the contact Tl.

During normal operation of the heatingsystem, and when there is no flow of steam through vent conduit 6|, the volume of the volatile fluid in the expansible fluid-thermostat is reduced and the bellows 64 is in its contracted position. I In such contracted position of bellows 64, the lower toggle arm 68 bears against the knob 12 and contacts 11 and I9 are closed to complete the circuits for the solenoid coils 32. Under these conditions the switches 40 associated with the 7 normal control exercise influence over the solevolatile fluid in the expansible fluid thermostat increases, whereby the bellows 6 4 expands. Ex-

pansion of bellows 64 imparts clockwise movement to lower toggle arm 68, and, when the coil spring H is moved past the straight line position of the toggle arms 61 and 68, both of the toggle arms move with a snap-action toward the left. With such snap-action the lower toggle arm 68 moves against the button 13, and the upper toggle arm 61 moves against the stop member 18. Operation of switch 66 in the manner just described separates contacts l1 and 19, whereby the circuit for the solenoid coils 321s broken and the latter are de-energized. Under these conditions the plungers 34 of the control devices 2| move downward by gravity so that the valves 34 are moved to their closed positions to shut off flow of fuel to the burners.

In order. to start flow of fuel to the burners l8 it is necessary to push the enlarged head 15 against the action ,of spring 16 to move the button 13 toward the bellows 64. This imparts counter-clockwise movement to lower toggle arm 68, and, when the coil spring H is moved past the straight position of the toggle arms in the opposite direction, the toggle arms move with a snap action toward the right. Assuming that there no longer is flow of steam through vent 6|, the bellows 64 will be in the contracted position shown in Fig. 2, whereby the toggle arms can move to the position shown with the lower toggle arm 68 bearing against the knob 12 and the upper toggle arm closing the contacts l1 and 19. The closing of contacts 11 and I9 completes the circuit forthe solenoid coils 32, whereby norcausing flow of air through said duct to the enclosure, a boiler, a heater for heating said boiler to produce steam in the latter, heating means arranged in said duct connected to receive steam from said boiler, said heating means being vented to atmosphere, control means responsive to a temperature condition afiected by said heating means for controlling said heater and hence the temperature of air in the enclosure, and means affected by flow of steam through said vent casioned, for example, by loss of load on said heating means resulting through operating failure of said air flowing apparatus, to modify the control exercised by said control means and reduce the heating of said boiler by said heater.

2. A heating system comprising a plurality of parts including a boiler, a heater for heating said boiler to produce steam in the latter, a heating element connected to receive steam from said boiler, said heating element being unobstructedly vented to the atmosphere, the aforementioned parts of said system being so constructed and arranged that, at a predetermined maximum rate of heat input to said boiler by said heater and a predetermined load on said heating element, the steam supplied to said heating element fills the latter substantially completely with the steam condensing in said heating element and substantially no flow of steam through said vent, and means operative responsive to a temperature condition afiected by said heating element to control said heater to reduce the heat input to said boiler below said definite rate and hence redube the supply of steam to said heating element, so that air can enter the interior of the latter through said vent and blanket oif part of reduce the heating efiect of said heating element.

3. In an air conditioning unit, an enclosure, a

duct connected to the enclosure, means for causing flow of air through said duct to the enclosure, an atmospheric pressure heating system comprising a plurality of parts including a boiler, a heater for heating said boiler to produce steam in the latter, heating means in said duct for transmitting heating effect to air flowing therethrough, said heating means being connected to receive steam from said boiler and being unobstructedly vented to atmosphere, the aforementioned parts of said heating system being so constructed and arranged that, for a predetermined maximum rate of heat input to said boiler by said heater and a predetermined load on said heating means, the steam supplied to said heating means fills the latter substantially completely with the steam condensing in said heating means and substantially no fiow of steam through said vent, and means responsive to rise in a temperature condition affected by said heating means to control said heater to reduce the heat input to said boiler below the definite rate and hence re-' duce the supply of steam to said heating means, so that air from the atmosphere can pass through said vent and partly fill the interior of said heating means to blanketpfi a. portion of the heat dissipating surface of the latter from the steam to reduce the heating effect of said heating means.

4. An atmospheric pressure heating system including a boiler, a heater for heating said boiler to produce steam in the latter, heating means connected to receive steam from said boiler, said heating means being vented so that air may pass into said heating means from atmosphere and steam may fiow from said heating means to atmosphere, and means responsive to flow of steam through said vent from said heating means into the atmosphere to render said heater ineffective to heat said boiler.

5. An atmospheric pressure heating system including a boiler, a heater for heating said boiler to produce steam in the latter, a plurality of control device's for controlling flow of fuel to said heater, said control devices having valves capable of assuming only closed and fully opened positions, heating means connected to receive steam from said boiler, said heating means being vented to atmosphere, control means for selectively controlling said devices to regulate the flow of fuel to said heater and means responsive to .flow of steam through said vent to render said control means inoperative to freely control said devices and cause said valves to assume their closed positions.

6. An atmospheric pressure heating system including a boiler, gas heating means for heating said boiler to produce steam in the latter, a plurality of valves each capable of assuming either a closed position or a fully open position for controlling flow of gas to said gas heating means, heating means connected to receive steam from said boiler, said heating means being vented to atmosphere, control means for sequentially controlling said valves to regulate flow of gas to said gas heating means and means responsive to flow of steam through said vent to render said control means ineffective to regulate flow of gas to said gas heating means and cause said valves to assume their closed positions.

7. An atmospheric pressure heating system as set forth in claim 6 in which said control means for sequentially controlling said valves operates responsive to a temperature condition affected by said heating element.

8. A heating system including a boiler, a heater for heating said boiler to produce steam in the latter, heating means having a vent and connected to receive steam from said boiler, means responsive to a temperature condition affected by 9. A heating system including a boiler, a heater for heating said boiler to produce steam in the latter, heating means having a vent and connected to receive steam from said boiler, control means responsive to temperature condition affected by said heating means for normally controlling said heater, and means operable when ,uncondensed steam passes through said vent from said heating means to terminate normal control of said heater, said last-mentioned means being manually operable to permit normal control of said heater by said control means when uncondensed steam no longer passes through said vent from said heating means.

boiler, an electrical control device for controllin flow of fuel to said burner, heating means connected to receive steam from said boiler, said heating means beingunobstructedly vented to atmosphere, and thermal means operative responsive to a temperature condition afiected by said heating means for controlling said device, the aforementioned parts of said system and said thermal means being so constructed and arranged that, with a predetermined load on said heating means, said thermal means acts to-cause predetermined maximum, heating of said boiler by saidheater so that said heating means will be substantially filled with steam and all of the steam will condense therein with practically no steam passing through said vent to the atmosphere.

11. A heating system including a boiler, a heater for heating said boiler to produce steam in the latter, heating means unobstructedly vented to atmosphere and connected to receive steam from said boiler, control means operative responsive to a temperature condition affected by said heating means for controlling said heater, and safety means operative responsive to the presence of steam in the unobstructed vent to modify the control exercised by said control means to turn the heater-oil? when steam flows through said vent.

12. The combination of heating means providing a chamber having a heat transfer surface, said chamber having means for admitting heat-- ing vapor thereto and draining condensate therefrom,a vent conduit connected to said chamber at a point remote from the region at which heating vapor is admitted thereto, said vent conduit being located so that condensate formed in said chamber normally cannot flow therethrough, means to supply heating vapor to said chamber so. that heating vapor flows in contact with said heat transfer surface toward said .vent conduit from the region at which heating vapor is admitted to said chamber, said vent conduit providing a passage through which heating vapor may pass from said chamber into the presence of a non-heating mediumat substantially constant pressure, such as atmospheric air, and through which non-heating medium may pass into said chamber when the latter is not completely filled with heating vapor, control means responsive to a temperature condition affected by said heating means for controlling said supply means to regulate the rate at which heating vapor is supplied to said chamber, said non-heating medium being displaced from said chamber through said vent conduit upon increase in quantity of heating vapor in said chamber and said non-heating medium entering said chamber through said vent conduit upon decrease in quantity of heating vapor in said chamber, the quantity of heating vapor in contact with said heat transfer surface being dependent upon the quantity of heating vapor in said chamber with respect to the quantity of non-heating medium therein, and means responsive solely to the presence of heating vapor in said vent conduit to modify the control of said supply means by said control means.

ALBERT Rl moms. 

